Little population-based data exist on foot biomechanics and foot disorders, and foot pathologies are often overlooked as important potential causes of physical limitations, impaired balance, and lower extremity dysfunction in older persons. These issues represent major public health problems that will only increase in importance as the population ages. The Framingham Foot Study is one of the first studies to examine the prevalence and the pattern of foot disorders and foot pain. For the past five years, the Framingham Foot Study has contributed substantially to understanding population-based prevalence of specific foot disorders and the role of these disorders upon physical limitation. Over the next five years, we are proposing in this competing renewal application to expand on this theme by examining the biomechanics of the foot in relation to physical limitations and lower extremity function, by using a refined measure of plantar pressure in each region of the foot. We plan to use data from plantar pressure scans collected over the past grant cycle in the Framingham cohort (n~3053), along with additional plantar pressure scans to be acquired in the ethnically diverse Johnston County cohort (n~3084). Using these scans, we will determine measures of peak pressures within specific foot regions as well as center of pressure excursion indices using well-defined engineering techniques and statistical tools. In addition, we propose to obtain specific data on foot disorders from the Johnston County cohort of older African-American and Caucasian men and women. We will use the data to examine the relation between plantar pressures in different regions of the foot in static and dynamic postures with the occurrence of foot disorders and lower extremity measures of function and dysfunction across the two ethnically and culturally diverse populations. Our four specific aims will examine the cross-sectional relation of 1) foot pressure measures between different age groups and ethnic groups in men and women from two population- based cohorts (Framingham Study and Johnston County Study), including center of pressure excursion index that indicates dynamic measures of pronation and supination, as well as peak load in specific regions of the foot;2) these foot pressure measures and specific foot disorders, foot pain, and ankle, knee and hip joint pain;3) these foot pressure measures and lower extremity function, specifically physical performance measures, muscle mass and leg muscle strength, as well as 4) the longitudinal determination of risk factors that will predict incident foot disorders over time. Based on preliminary data, this study will provide new and important information about the role of foot biomechanics and disorders upon lower extremity function in men and women. No other project has linked detailed information on foot disorders in older men and women to comprehensive function, lower extremity performance, muscle status, and falls in diverse populations. PUBLIC HEALTH RELEVANCE: This study will provide new public health information of the importance of foot biomechanics and specific foot disorders in older populations of Caucasians and African-Americans, as these issues along with lower extremity disability and falls are serious burdens for many older adults. Understanding of the factors proposed in this project is essential from the public health standpoint because foot disorders are so poorly understood in the community, and are potentially modifiable through treatment.